You raise some interesting questions and valid criticisms (to a point).
I face two primary limitations on my photography, so far as whom I photograph: self-selection bias and limited resources.
I began writing a very, very long and detailed response — too long for one post… so, I’m going to respond in a series of posts, starting today.
Follow this tag: working with what you’ve got
As for the “one” woman of color (there’s two in my demure gallery, two in my environmental gallery, and four in my studio gallery) and “one” woman of size (there’s there, across the three aforementioned galleries), four have retired from modeling, I’ve worked repeatedly with a number of others, one I refuse to work with after two bad experiences (which had nothing to do with her appearance) and another — with whom I’ve not worked since 2011 — that I’m desperately trying to coordinate with, working around her career, personal and family constraints.